[1] P. BARTOLO V. BENCI D. FORTUNATO:
Abstract critical point theorems and applications to some nonlinear problems with "strong resonance" at infinity. to appear.
MR 0713209
[2] V. BENCI:
A geometrical index for the group $S^1$ and some applications to the research of periodic solutions of O.D.E. 'S. to appear.
Zbl 0447.34040
[3] G. CERAMI:
Un criterio di esistenza per i punti critici su varietà illimitate. Rendiconti dell' Academia di Sc. e Lett, dell' Istituto Lombardo 112 (1978), 332-336.
Zbl 0436.58006
[5] K. THEWS:
$T$-periodic solutions of time dependent Hamiltonian systems with a potential vanishing at infinity. to appear.
MR 0612616 |
Zbl 0467.35009